Clamp for leather-stretching machines.



No. 685,253. Patented Oct. '29, I901.

J. CALDWELL.

CLAMP FOB LEATHER STBETCHING MACHINES.

(Appliation md Dec. 1, 1900.)

(No Model.)

71 261256566 4 [72 0672507 Jo m. cam wail w L B I kid 5107 02654 T UNTED STATES- PATENT OFFICE.

JOHN OALDW'ELL, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO THE W. S. NOTT00., OF MINNEAPOLIS, MINNESOTA, A CORPORATION.

CLAMP FOR LEATHER-STRETCHING MACHINES.

SEECIFIGATION" forming part of Letters Patent No. 685,253, dated October29, 1901.

Application filed December 1, 1900. Serial No. 38,313. (No model.)

To aZZ whom it may concern.-

Beit known that I, JOHN CALDWELL, a citizen of the United States,residing at Minneapolis, in the county of Hennepin and State ofMinnesota, have invented certain new and useful Improvements in Clampsfor Leather- Stretching Machines, of which the following is aspecification.

My improvements relate to devices for engaging marginal portions ofleather to hold it during the operation of stretching it on astretcher-frame. Heretofore, so far as I am aware, the clamps designedfor engaging successive marginal portions of leather and to beindependently connected to the stretcherframe have consisted ofgripping-jaws permanently hinged together.

It is the principal object of the present improvements to dispense witha pivot or hinge for connecting the clamp members and to provide thelower or stationary jaw with a transverse abutment having a verticalrear Wall and the upper or movable jaw with a pendent transverse fiangeor rib arranged to engage and slide vertically upon such abutment-walland means for operating the upper jaw bodily in vertical directiontoward or away from the lower jaw without changing the parallelism ofthe two jaws. The overlapping parts of the jaws are thus made tocooperate in withstanding the tension of the leather when in service insubstitution for the hinging connections of the other form of clamps.Such improvements are illustrated in the accompanying drawings, in whichFigure 1 is a side elevation of one of the improved clamps, togetherwith a portion of the stretcher-frame head. Fig. 2 is a plan view of theclamp. Fig. 3 is a detail showing the device for raising and loweringthe upper jaw, and Figs. 4: and 5 show variations of the means forconnecting the clamp to the stretcher-head.

In the drawings, 1 designates a surfaceplate or other suitable portionof one of the heads of a stretcher frame, to which the clamp is to betemporarily secured during the operation of stretching a piece ofleather. The lower member or base 2 of the leatherclamp consists of aplate, preferably about two to two and a half inches wide and about twoand a half to three and a half inches long, having a transverse rib orraised portion 3 in rear of the gripping-face, designed as a guiding andresisting abutment for the rear portion of the upper clamp member. Thelatter member or jaw 4 may be a flat metal plate having a downwardflange or rib 5 arranged to engage the rear wall of the abutment 3. Themovement of the jaw 4 toward or away from the fixed jaw 2 is preferablyeffected, as shown, by means of an upright screw 6, secured to thelatter and extending through an opening in the former. A suitable nut 7on the screw above the jaw 4 is connected to a sleeve 8 in the openingin the jaw, the sleeve having suitable flanges 9 and 10, respectively,at the opposite surface of the jaw, whereby the nut is swiveled to thejaw. The movable jaw being thus carried by the nut on the screw, it canbe readily raised or lowered and when desired may be made to press amarginal portion of leather 12 upon the lower jaw to grip and hold theleather during the operation of stretching it. The engagement of theflanges 5 with the abutment 3 serves to retain the upper jawin operative connection with the lower jaw and enables the clamp to hold theleather during the operation of the machine.

In order that the leather may be gripped firmly, it is desirable toprovide the jaws with intermeshing transverse ribs 11, as shown, orother suitable irregularities of surface.

The temporary connection of the clamp to the stretcher-head may be madein any de-' sired way. Several ways of making such connection are shownin the drawings.

In Figs. 1 and 2 the connection is illustrated as being made by means ofa pin or key 13, passed through a slot 14 (or it might be one of anumber of holes) in the rear portion of the base-plate 2 into one of aseries of holes in the plate 1 on the stretcher-head.

In Fig. 4: the plates 1 and 2 are shown as having correspondingtransverse serrations 15, adapted to intermesh and hold the clamp inplace under tension.

In Fig; 5 the base member 2 is shown as pivoted on a stud l6, projectingupward from an underlying plate or bar 17 through an open ing in theplate 2, whereby the clamp maybe turned in a plane parallel with theplates 1 and 17. The plate or bar 17 may be connected to thestretcher-head in the manner above described or in any other desiredway.

As the objects aimed at and the operations described could beaccomplished by modifications of the devices shown, I do not wish tolimit my claims to the specific forms and arrangements of the meansillustrated and described.

The improvement herein disclosed relative to the manner of connectingthe holder to a part of a stretching machine is not here claimed, but isreserved to be claimed in my pending applications, Serial No. 1,424.,filed January 15, 1900; Serial No. 9,199, filed March 19, 1900; SerialNo. 40,215, filed March 26, 1900; Serial No. 21,061, filed June 21,1900, and Serial No. 10,128, filed March 26, 1900.

Having described my invention, What I claim is- 1. In a leather-clam p,the combination with a base member or plate provided with a transverseabutmenthavingits rear wall substantially perpendicular, of a movableupper member provided with a shouldered portion slidable vertically uponsaid abutment, said base and upper members being provided withleather-engaging means, an upright screw in the base member, and a nutswiveled on the upper member for raising and lowering the latter memberbodily while maintaingits parallelism to the base member, whereby saidabutment is adapted to resist the tension of the leather upon the upperclamp member, substantially as set forth.

2. The combination with the head of a stretching-frame, of aleather-clamp comprising a base member adjustably connected to said headand provided with a transverse abutment having its rear wallsubstantially perpendicular, a vertically-movable member having ashouldered portion adapted to engage such abutment, whereby saidabutment is adapted to resist the tension of the leather upon the upperclamp member, and means for effecting the vertical movements of theupper member, substantially as set forth.

In testimony whereof I have hereunto set my hand this 22d day ofNovember, 1900.

JOHN (JALDWVELL.

In presence of P. H. GUNoKEL, A. L. WHELAN.

